Demetrios Laskaris Leontares or Leontarios (Greek: Δημήτριος Λάσκαρις Λεοντάρης, died 6 September 1431) was an important Byzantine statesman and military leader of the early 15th century, serving under the emperors Manuel II Palaiologos (r. 1391–1425) and John VIII Palaiologos (r. 1425–1448).